Pitching for Boston's Triple-A Pawtucket affiliate, Buchholz walked one and struck out two. He threw 60 pitches, 33 for strikes.
Buchholz has been one of the best pitchers in the American League this season, going 10-4 with a 2.45 ERA. The righty strained his left hamstring running the bases in a game at San Francisco on June 26.
He is expected to re-join Boston's rotation for Wednesday afternoon's game at Oakland. Felix Doubront filled in for Buchholz on Friday night at Fenway Park against the Rangers.